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991.
李绿怡 《四川建材学院学报》2010,(2):90-92,99
采用电感耦合等离子体原子发射光谱法同时测定魔芋精粉中铅、铬、镉、砷、汞5种元素的含量,其检出限分别为0.0102、0.0009、0.001、0.028、0.004 mg.L-1,测定回收率在98.0%~103.0%之间,RSD(n=10)为0.5%~1.6%。所建立的元素分析方法其准确度和精密度均符合要求,应用本方法测定实际样品,结果令人满意。 相似文献
992.
In order to improve the pyrotechnical reagent with potassium perchlorate,composite catalyst of active carbon supporting transition metal oxides (TMO),Fe2O3 and CuO,were prepared and added into pyrotechnical reagent with potassium perchlorate.Accelerating rate calorimeter (ARC) was used to study the catalysis of pyrotechnical reagent which is consisted of potassium perchlorate and composite catalyst.Composite catalyst of both Fe2O3 and CuO supported by active carbon can catalyze pyrotechnical reagent with potassium perchlorate.Furthermore,it can lower the apparent activation energy and accelerate the reaction with a smaller quantity than that with Fe2O3 and CuO.The maximal reaction rate of pyrotechnical reagent with potassium perchlorate mixed with Fe2O3/active carbon and CuO/active carbon is 8.31 min-1 and 9.13 min-1,which is 1.74 times and 1.91 times of pyrotechnical reagent mixed with no catalyst;time to maximal rate was 18.99 min and 1.96 min respectively,which is lower than pyrotechnical reagent mixed with no catalyst by 86.46% and 98.67% ;the apparent activation energy is 368.10 kJ·mol-1 and 325.29 kJ·mol-1,which is lower than pyrotechnical reagent mixed with no catalyst by 31.89% and 39.81% respectively. 相似文献
993.
以ZrOCl2.8H2O和Ni(NO3)2.6H2O,Cr2O3,NH4HCO3为原料,采用缓冲溶液法(一种改进的共沉淀法)制备出复合氢氧化物,将其焙烧得到复合氧化物粉末,最后通过高温还原制备得到NiCr-ZrO2复合粉体材料.通过TG-DSC,XRD,激光粒度仪等现代分析技术对材料的热物性、组成、粒度分布进行测定并研究复合材料热胀系数与其成分组成之间的关系.结果表明,NiCr-ZrO2复合材料的热胀系数随其金属含量的增加而增大. 相似文献
994.
Ming-ji Huang ) Xiu-ping Dong ) Guo-quan Liu ) ) School of Mechanical Engineering University of Science Technology Beijing Beijing China ) School of Mechanical Engineering Beijing Technology Business University Beijing China ) School of Materials Science Engineering China 《北京科技大学学报(英文版)》2010,17(1):75-79
Based on the analysis of the preparation of metal rubber (MR) and two pivotal hypotheses,the uniform distribution and the unaltered topological structure of wires in the radial direction of columns in the punch process,a 3D parametrical model was established based on four approaches:helix-making,planar roughcast-weaving,planar roughcast-rolling,and 3D roughcast punching.In the modeling process,5 lattice types of weave patterns in planar roughcast were put forward,and 10 quantificational modeling parameters ... 相似文献
995.
Spherical cavity expansion model is often used to study the mechanic characteristics of pressure sensitive mediums. The most important one we do in the paper is that we construct a four-region model with σθ≠0 in damage region,which is different from what Satapathy did before and is more reasonable. By adopting this model,different constitutive equations were constructed by different method-elastic mechanics in elastic region,damage mechanics and fracture mechanics in damage region,and macro-micro mechanics theory in plastic region. Then using Durban's self-similarity assumption,the control differential equations with boundary conditions were established,and the static numerical solution of stress field and displacement field in the three different regions of elastic,damage and plastic area were discussed respectively. Results showed that this four-region model can describe precisely the mechanic characteristics of pressure sensitive mediums under initial pressure. 相似文献
996.
To research the approach of predicting composites fatigue life,the cumulative fatigue damage of fiber-reinforced plastic laminates(FRP) was investigated,and based on the complex exponential function,the residual strength model was obtained. This model can accurately describe the propagation of cumulative fatigue damage of FRP in three stages,especially in the initial stage and the ceasing stage. Applying this model in the experiment with two loading cycles,it can be found that the prediction result has good coincidence with experimental data. So a reliable residual strength model can be provided for studying the cumulative fatigue damage of FRP. 相似文献
997.
通过检测不同条件下Li+离子在混凝土中的浓度变化和滞留量,考察了再碱化过程中物料的传递方式及其在该过程中的作用.结果表明:在电场作用下,锂离子通过电渗和电迁移由溶液向混凝土迁移;再碱化过程前期主要靠扩散实现,后期则主要由电渗和电迁移来完成. 相似文献
998.
999.
1000.
料仓贮料压力计算是料仓结构设计中的重要一环,其计算方式分为深仓和浅仓两种。本文通过具体算例分析,对钢筋混凝土料仓和钢料仓在贮料压力计算中应注意的压力复核问题进行了总结,提出了较实用的解决办法。 相似文献